But it seems to me that, rather than a change in underlying sentiments -- that is, more prevalence of quote-unquote extreme, alienated, nonmainstream, populist, pox-on-both-their-houses viewpoints -- what has instead changed is that these viewpoints have become much more visible.

Remember the intense attention given to the PUMA (Party Unity My Ass) activists last year? Talk of these hardcore Hillary supporters filled the airwaves when I went to the Democratic Convention last year. But I saw no more than a dozen or so PUMA types on a street corner a mile from the convention site. As for those in the hall, I never heard anything less than enthusiastic support for Barack Obama, even among the most devoted Clinton delegates.The internet helped those inclined to join the PUMA movement find like minds, and the news media gave them far more attention than their numbers and influence warranted. At the end of the campaign it turned out that, for all the publicity, the PUMAs had a negligible effect on the election.The media, old and new, tend to magnify the importance of relatively minor segments of the population, but the broad, underlying spectrum of views on political issues are not, for the most part, subject to the whims of the never ending news cycle.